I just created a text file (.TXT) in Notepad (expecting it to be plain text) and emailed it so I could pick it up on my Nexus 7 tablet. None of the text editors on the tablet can interpret the file (I've tried several times now, including some old .TXT files).
On investigation it seems that Notepad doesn't handle plain text at all - it allows formatting (fonts, bold, italics etc.).
Yet all the searches Ive done on the Internet say that Notepad does not support formatting, only plain text.
I'm using W7. But I've also tried XP - same again.
I think you may be using WordPad instead of NotePad. WordPad supports formatting and saves the file as RTF. Your tablet should have software that supports such files if you have a text editor on board.
Barking up wrong tree - I assumed that as the Nexus text editors can't interpret any text files created with Notepad, that Notepad was inserting font formatting info - as one of the options on the Notepad Format menu is Font, but seems that just changes the display font, not what is saved in the file. So will have to delve further, but can't do now as have to cook dinner for SWMBO.
Worked aroundissue for now - attached Nexus to PC and copied file across. Opens fine then. But if I email it to myself and then open the email on Nexus and save the attachment, can't interpret the file - very strange. Don't have time to look into it more now.